Diffuser Porn

The blue one is the front-engine Mustang IMSA GTP car of circa 1983-84, while the raw black one is its mid-engined Mustang Probe counterpart. Both were encountered yesterday during a visit to Jack Roush's private car collection in Livonia. More photos from the visit here...

What's stupid is thinking 7degrees has any relevance to generating downforce on a racing car

yes, apparently vortex management needs a whole new attitude to diffuser design, and I'd ignored the rear wing's effect on the diffuser as well. Flicking through Katz I see that 14 degrees is a typical upper limit for the experiments there, although the CL is still increasing even at that value.

The 7 deg. thing is really a non-starter. For the most part, you just stick as much tunnel on the car as possible. Yes, your efficiency drops, but it's still better than the next best thing, so you for for it. It's basically a function of packaging or the rules.

I can't post pictures and I have given up on learning how to.
But in 1999 I was in the museum at Bedford where I saw the Hurtibise built Roadster.
Out of the bodypanels of the last versions of that car they built up another car. But man that particular version of that old roadster had a large tunnel ......

Watching the tunnels on the Indycars of the early 80's up to about, say '87....
To this day it still surprises me that the cars of that era could surpass 200 mph averages because the downforce on the straights must have been tremendous: good for corners but on the straight....